'96 GL1500 SE. Got the bike last spring and it had a bad low speed wobble so I replaced the steering head bearings along with the other new to me bike stuff. When I'd gotten far enough in to get to the bridge top nut I noticed it wasn't even hand tight, it had actually backed off a little. There were marks on it showing it had been removed with a chisel, so I assumed that PO (or the joke that passes for a Honda dealer here) didn't have a 30mm socket to torque it back down to the 72lbs specified. After removing the bridge and lock nut, I discovered the adjusting nut was barely hand tight. After replacing both top and bottom bearings and races I seated the bearings as per the FSM and left the adjusting nut torqued to 14lbs and the top nut to 72. I've put around 7k miles on it since then and the last couple of weeks it's felt like there was something going on with the bearings again. Since the FSM calls for checking them at 8k, today I pulled it apart again to discover the top nut which I torqued to 72 lbs was less than hand tight again. The adjusting nut was still around the 14 I put on it before. The fork pinch bolts were still tight too. What's going on here?

I have never personally replaced or adjusted the steering bearings (so why am I posting). I spend a lot of time reading in this and other forums. I tried to find a page discussing the proper technique for seating the bearings, as well as the races, with no luck. I have read about it, and the page I'm thinking of, referred to issues such as you are having. The problem as described, regarded the necessity to be certain the races are properly seated in the steering tube. Apparently this can be a problem. It described a case where the races were not seated, and proceeded to cause the bearings to gain too much looseness, as the races seated after some driving time had passed.
Anyway, I would suspect that might be the issue you are having. The races have seated further into the steering tube during the 7K miles you have now ridden. I suspect the bearings are still good, just needing to be tightened to specs, and then, maybe rechecked again, maybe a couple of thousand miles down the road to verify no more adjustment is needed. Hope that helps.

Lastly, the locknut goes on, finger-tight only, lining the lock washer tabs up with the slots in the locknut:

The tabs then get bent up into the locknut:

The upper bridge gets installed, then the bridge nut is installed and torqued to 72 ft-lbs:

The idea is this: the upper stem is sandwiched very tightly between the bridge nut and the locknut. This prevents either the locknut or the bridge nut from loosening. Because the locknut is tied to the bearing adjustment nut with the lockwasher, it prevents the bearing adjustment nut from loosening as well, even though it is torqued to only 14 ft-lbs.

If the locknut or lockwasher are missing, things won't work correctly, you'll end up either putting too much torque on the bearing adjustment nut, or the bridge nut will work its way loose.

Thanks for the replies, guys.
Bluewaterhooker0, as far as I could tell, the races were both fully seated. The fact that the adjusting nut was still torqued to the correct value leads me to believe that this is the case.

WA, the lock nut and washer were both installed correctly. I'd used your guide and the service manual. The only thing I did differently was loosening the pinch bolts after the top nut was torqued down to try to get the top of the tubes a little more even with the bridge. Would this have contributed to the top nut backing off? The threads on the stem and the underside of the top nut both had grease on them, but I wouldn't think at 72lbs that would have helped it back off. If anything, it would have helped get a correct torque value.

I got it all buttoned back up yesterday. This time I cleaned the stem threads and nut of grease and snubbed the top nut down before tightening the pinch bolts, then torqued the nut. The wobbles are gone again I'll keep an eye on the torque on the top nut for a while though. Still has me puzzled how that nut could back off like that.